Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

As an installer, how does that 'rough in boot' fit for the large HE duct sizes? a standard 2 X 4 wall is not too shallow for those to fit?

The manufacturer is really vague as far as seer ratings for the air handler as far as I can tell. since the seer ratings need to match between ahu and condenser - cmajerus, have you used any particular condenser with good results?

As an installer, how does that 'rough in boot' fit for the large HE duct sizes? a standard 2 X 4 wall is not too shallow for those to fit?

The manufacturer is really vague as far as seer ratings for the air handler as far as I can tell. since the seer ratings need to match between ahu and condenser - cmajerus, have you used any particular condenser with good results?

we always used the ttb trane condensers on the ones we did, we heard conflicting stories on seer ratings with HI V's the mfg says they stay the same as with standard indoor units, others have told us they cut the seer rating down considerably, haven't installed one since the 13 seer mandate so not sure what we would use now.

I have over 300 installed

We have installed them in every possible application you can imagine. I have three of them running in my house now and two more in my apartments next door.

Have I had any problems with them??? Why of course, almost every one of them has had some sort of problem. But then, what doesn’t have problems? It's not a product you can install and just walk away from, they are constant mantainance at first, but once the bugs are worked out they run fine with minimal routine mantainance. My partner wants me to stop using them, as he sees them as a major lost to the company profitability and I have to reluctantly agree with him.

For the most part we have returned to installing conventional low velocity systems as our mainstay but still do Hi-V for certain applications. The Hi-V systems cost almost 2K more than the Lo-V system.

Have I had any problems with them??? Why of course, almost every one of them has had some sort of problems. But then, what doesnt have problems? It's not a product you can install and just walk away from, they are constant mantainance at first, but once the bugs are worked out they run fine with minimal routine mantainance.

I have installed a unico system, do you mean the ESP Hi-Velocity system is more troublesome than the others (like Sacepak)? or they are all, as a catagory, a little buggy?

Any comments on the HE large duct or the rough in boots, or the EPC variable speed motors?

Problems... What problems?

I can't comment on other brands as we were exclusively Hi-V systems. ESP changed their load calculation software design which led us to be under sizing several units (about 10 of them) before we caught onto the problem. This little mistake ended up costing us eighty grand to fix. ESP helped us for a while, but later turned their back on us and left us to resolve the rest of the problems. We haven't installed anymore of their system since then.

Another costly problem that we encountered was the stratification that was taken place in the poplar, older, multi story homes in our area. A single system can't overcome this effect and leads to overheating in the summer and under heating in the winter for the second and third floor areas. ESP was adamant their systems would homogenize all the air and the whole house would be within 1 degree (+ or - 1). It doesn't work and we had to install additional equipment at a huge cost to us and our customers.

Next problem is balancing out the refrigerant charge... No easy task, to say the least, sometimes it would take several tries over several days to get it regulated.

ESP had flex duct failures issues as well. The end termination was just a 2" vac. pipe coupling taped in place that would fall apart. When our customers would complain that some or all the vents weren’t working we would find them completely detached. Not a big problem if found them early on or they were where we could get to them, but a major problem if they were in walls or inaccessible areas. ESP helped us at first, but soon grew tired of the problem and though the blame back onto BioFlex and washed their hands of it. BioFlex is a Canadian Co. who sold the product indirectly and couldn't understand English... So you know who ended up paying...

Last, but not least, Condensing units: Any unit that had a Bristol compressor in it was in for a short life, real short.

ESP tells me that I'm the only one that has ever had problems with their products... I guess they're right, but it sure seems funny that two of our local supply house chains have switched to Unico. It must be they are getting a better deal on them.

I can't comment on other brands as we were exclusively Hi-V systems. ESP changed their load calculation software design which led us to be under sizing several units (about 10 of them) before we caught onto the problem. This little mistake ended up costing us eighty grand to fix. ESP helped us for a while, but later turned their back on us and left us to resolve the rest of the problems. We haven't installed anymore of their system since then.

Another costly problem that we encountered was the stratification that was taken place in the poplar, older, multi story homes in our area. A single system can't overcome this effect and leads to overheating in the summer and under heating in the winter for the second and third floor areas. ESP was adamant their systems would homogenize all the air and the whole house would be within 1 degree (+ or - 1). It doesn't work and we had to install additional equipment at a huge cost to us and our customers.

Next problem is balancing out the refrigerant charge... No easy task, to say the least, sometimes it would take several tries over several days to get it regulated.

ESP had flex duct failures issues as well. The end termination was just a 2" vac. pipe coupling taped in place that would fall apart. When our customers would complain that some or all the vents werent working we would find them completely detached. Not a big problem if found them early on or they were where we could get to them, but a major problem if they were in walls or inaccessible areas. ESP helped us at first, but soon grew tired of the problem and though the blame back onto BioFlex and washed their hands of it. BioFlex is a Canadian Co. who sold the product indirectly and couldn't understand English... So you know who ended up paying...

Last, but not least, Condensing units: Any unit that had a Bristol compressor in it was in for a short life, real short.

ESP tells me that I'm the only one that has ever had problems with their products... I guess they're right, but it sure seems funny that two of our local supply house chains have switched to Unico. It must be they are getting a better deal on them.

your not the only one, and my guess there are more than just 2 companies out there. We only had 2 major problem child jobs, but neither are perfect to this day, just tolerable. One question I would have is are there any other indoor units that would be compatible to the duct system installed for the HI-V? ie: round metal duct, not fiber pipe.

ESP changed their load calculation software design which led us to be under sizing several units (about 10 of them) before we caught onto the problem.

Another costly problem that we encountered was the stratification that was taken place in the popular, older, multi story homes in our area. A single system can't overcome this effect and leads to overheating in the summer and under heating in the winter for the second and third floor areas.

Next problem is balancing out the refrigerant charge... No easy task, to say the least, sometimes it would take several tries over several days to get it regulated.

ESP had flex duct failures issues as well.

Last, but not least, Condensing units: Any unit that had a Bristol compressor in it was in for a short life, real short.

Of these problems it seems that stratification can be overcome with zoning or something similar. stinks they insisted that they could overcome the problem some other way. looks good on paper...we all know how that goes.

as for the rest, it seems as though they may have been overcome with fine tuning to the equipment. Was that your experience? how many of these issues are currently issues still, and how many were issues for you till the end (besides the improper sizing of the equipment, which CAUSED the end)

It seems that with 300 units installed, you found at least some of the issues were addressed, or that the issues were infrequent, but beastly when they were present.

It seems that a multi-stage condenser is a must for any system with a variable speed blower to allow for the lower loads. that may be the source of the compressor failures. correct me if I'm wrong.

I have been involved with the manufacturing side a little, so I may come across as slightly more... tolerant than some.

Thanks again for the input, good to go into a new product line with your eyes open.

we always used the ttb trane condensers on the ones we did, we heard conflicting stories on seer ratings with HI V's the mfg says they stay the same as with standard indoor units, others have told us they cut the seer rating down considerably, haven't installed one since the 13 seer mandate so not sure what we would use now.

What i learned was the system at best would get up to 12 seer, this is why unico fought to start up their own industry, " HVDS ".

We use the lennox 15 seer in areas where noise is a problem. Other than that we use the 13's.

What i learned was the system at best would get up to 12 seer, this is why unico fought to start up their own industry, " HVDS ".

I read the applications unico, spacepak, and EPS submitted for exemption from the 13 seer mandate. the issue was mainly the blower fan having to generate a higher static due to the duct design. this put them over the top for overall power consumption, thus the 10-12 seer ratings. strictly speaking, it seems this would not affect the evaporation characteristics that is at the heart of the requirement to match 13 seer condensers to 13 seer evaps.

of course one could also argue that, if left unregulated, there is no reason for them to upgrade a thing, meaning regardless of what the fan is doing the unit remains a 10-12 seer evap coil, making the issue of matching to an appropriate condenser moot.

THis mod allows you to set the evap temperature, and actually de-rate the evap to match the load. this eliminates icing, and provides thermostatic control of your evap's temp. then your TXV rides it's 10 degree superheat on top of whatever evap temp the Rawal is set to. this means the rawal garantees the 40 degrees ESP wants, and the TXV garantees the 10 degree superheat. At least in theory anyway, I'm conferring with the manufacturers to make sure I'm reading their literature correctly.

Also it allows your Condenser power consumption to modulate continuously as if it was a multistage, boosting your seer rating, while seemingly compensating for the one most serious problem from an installer's viewpoint which is getting the charge right.

There is a lot more info on that Rawal control that you can only get if you e-mail and ask for it.

Something else I noticed as I play with thermodynamics online (FUN!!)
The ARI website publishes data for compatible units, and their actual output. Plugging in models for the Hi-Velocity system and the nearest Unico equivalent matched to the same condenser we get the following results:

The crux of the issue here is airflow over the evap, the minimum being affected by the ability of the condenser to mudulate it's oputput (stage) to match varying loads. you'll see a formula in there of 3.5 taps per ton per zone minimum for single stage condenser, 2.5 per tonm per zone for multistage. that is - for a 3 ton system